The idea of the musical work as a unified whole is one has dominated analysis and criticism for two centuries. Many musicians before and since Schenker have commented particularly on various types of motivic unity - pointing out connections between the various themes of a work.

By the end of his career Schenker saw the tension span of the fundamental structure as the main unifying force but his theory of layers or levels opened up new and interesting possibilities for a more profound sort of motivic analysis.

His monograph on Beethoven's Fifth Symphony (written in 1926) is an excellent example of this approach. Instead of looking for connections on the surface in the way that traditional motivic analysts did, Schenker discovered what he called 'parallelisms' that penetrate across the various layers of this much-discussed work.

One of the motivic parallelisms that Schenker discovered in the first movement of Beethoven's Fifth was an incomplete neighbour note that appears repeatedly both on the surface of the music and deep below it:

The extract below shows the first example of this motif - marked with long stems on the music:

This incomplete neighbour note is immediately extended over a longer span of music with more decoration:

In the above examples, the D is the neighbour note because it is conceptually dissonant - supported by the dominant (G) but dissonant against C (remember the work is in C minor). The motif also appears in the foreground (on the surface) of the music but now it is an accented appogiatura - the first note is dissonant rather than the second:

Here is one more example, where the neighbour note figure (now c - b natural) is concealed behind arpeggiations. Schenker suggested that this kind of subtle, concealed connection both unifies the work and makes it organic - the surface of the music grows out of this simple seed (see Why? section of SchenkerGUIDE for more on organicism).